fly ash concrete: future foundations?
TRANSCRIPT
Fly Ash Concrete: Future Foundations?5-2002
Follow this and additional works at: http://opensiuc.lib.siu.edu/uhp_theses
This Dissertation/Thesis is brought to you for free and open access by the University Honors Program at OpenSIUC. It has been accepted for inclusion in Honors Theses by an authorized administrator of OpenSIUC. For more information, please contact [email protected].
Recommended Citation Pairsh, Rebekah, "Fly Ash Concrete: Future Foundations?" (2002). Honors Theses. Paper 141.
I I
I I I I I I I I I I Fly Ash Concrete: Future Foundations?
I by
I I
I I
I would like to thank Dr. Gerald Nelms ofthe English Department at Southern Illinois University, Carbondale for his invaluable help and advice.
I I would also like to thank Dr. John S. Mead, Director ofthe Coal Research Center at
Southern Illinois University, Carbondale, for lending much ofthe materials used in this thesis.
I I I I I I I I I
I I I I I I I I I I I I I I I I I I I
Fly Ash Concrete: Future Foundations?
Table of Contents
Advocates ofFly Ash Concrete 5
Opponents ofFly Ash Concrete 7
Debate Summary
I I PROLOGUE
It was Summer 2001. Marion Memorial Hospital ofMarion, Illinois, a small regional
I hospita~ announced its intention to build a new hospital complex that would triple its
current size. The Hospital spokesman, Tom Keirn, announced that the Hospital's
I I contractor intended to use fly ash (also known as coal ash) concrete in the buildings.
Some scientists, engineers, and environmentalists believe that fly ash material is
I environmentally safe and structurally sound. Others, however, do not. Suddenly, the
celebration ofthe new Hospital turned into controversy.
Throughout the past thirty years, many studies of the feasibility ofusing fly ash concrete
I have been conducted. Some of the scientific results were negative, including one where
the structures built collapsed 95 percent of the time. However, the majority of the
I scientific results have been positive. In one study, the strength of the concrete was found
to be better in fly ash concrete than in regular aggregate concrete. In addition to
I questions about strength, there are also questions about environmental safety. The debate
between environmentalists is one of safety for humans and the environment. Although
I fly ash is considered by most to be environmentally safe, no one can be 100 percent sure
whether daily exposure to fly ash is safe for humans to be exposed to, or if fly ash
I concrete releases dangerous chemicals into the groundwater.
I I
I I Complicating the issue even further is the lack ofcommunication that often accompanies
the use of fly ash concrete. Marion Memorial Hospital, its engineers, and the City
I Council never clarified their reasons for using fly ash concrete. As a matter of fact, fly
ash is not really being used in the Marion Memorial Hospital concrete. They are using
I bottom ash, a denser byproduct ofbuming coal that is considered safe by aU experts.
There are no buildings currently being built or that have been built with fly ash in this
I area. According to Ray Serati, reporting for The Southern Illinoisan newspaper on the
Hospital, "The project incorporates the use ofcoal bottom ash, a coal combustion by
I product, in concrete support piles for the hospital's new Medical Office Building and
Power House" (1). The project calls for the use of200 tons ofbottom ash from
I Springfield's City Water Light and Power's (CWLP) plant complex to supplant the
aggregate that is normally used in concrete.
I Still, to this date, many Marion citizens do not realize that the new complex is not being
I built with fly ash. Not only this, they also do not understand the difference between fly
ash and bottom ash. Marion Memorial Hospital and the engineers of the project do not
I seem to be concerned enough with the misconceptions of the public to come forward and
explain the issue to the community and this lack ofcommunication with the public could
I become a serious public relations problem. The lack of information given to Marion
citizens is astounding. The problem Marion citizens are faced with is that no scientist,
I engineer, public relations official, or anyone else for that matter has informed the public
about the safety ofa building composed ofbottom ash or fly ash. In doing research on
I this matter, it becomes evident that the scientific community is at a loss in how to
communicate the benefits ofusing coal ash, specifically fly ash, to the public. This
I thesis, then, will attempt to define and explain fly ash in layman's terms and hopefully,
will answer some common questions and amend some misconceptions about fly ash
I concrete.
I I FLY ASH DEFINED
I When coal is burned to create energy, specifically electric power, fine coal particles
become airborne. These airborne particles are called fly ash because they literally float
I through the air. Because of the Clean Air Act, which will be discussed in more detail
later, the fly ash particles must be collected. According to the Dictionary of Coal
I Science and Technology, these airborne particles would normally be expelled with the
gas out of the smoke stacks if it were not gathered by electrostatic precipitators (Merritt
I 149-150).
I Fly ash is collected in four different ways, but it generally uses the aid ofan electrostatic
I precipitator. The electrostatic precipitator is an apparatus that is attached to the smoke
stacks ofcoal-fired power plants. The fly ash particles have a natural static-cling, and
I this device is used "to remove the fly ash from the stack gas and to collect it" (Merritt
133), presumably with the opposite electric charge. According to Coal Processing and
Pollution Contro!, particulate (fly ash) emissions are also controlled by cyclones, wet
I scrubbers, and fabric filters - also known as a 'baghouse' (Edgar 302) - the form of
collection Southern Illinois University at Carbondale uses.
I I The Electric Power Research Institute's (EPRI's) Fly Ash Structural Fill Handbook
defines fly ash as:
a by-product of the combustion process necessary for the production of
I electrical energy at modem power stations which burn fossil fuels. It is the
very fine, light dust which is carried off in the stack gases from the boiler
I units and collected by the air pollution control equipment. Fly ash is
composed of the noncombustible mineral matter present in coal and any
I carbon which remains unburned due to incomplete combustion....
(Section 2, Page I)
I As one may discern from the definitions above, fly ash is a powder-like substance.
I However, the particles may be shaped in various sizes and compositions, depending on
I 3
I
I I the type ofcoal that is being burned. No matter what type ofcoal is being burned,
according to the federal government, fly ash only has two different classifications.
I . J'),.
.,..,-;1.0'o·V .: J'
' .. ~. -. --.....,/ I Class F Fly Ash Class C Fly Ash
I Class F fly ash is more pozzo1anic (glassy) in nature, making it ineffectual for use in
concrete. Class C fly ash, on the other hand, contains more calcium making it more
I suitable for use in concrete. Over the last three decades, many attempts have been made
to develop a useful concrete containing 15-20% fly ash. This new concrete is now being
I tested.
Miscellaneous
I I
Fly ash is utilized in many different ways. The Electric Power Research Institute's Final
Report in March 1992 noted that in addition to its use in concrete, fly ash "has been used
I in highway construction work as an embankment material, in agriculture as soil
amendments, [and] in metals and plastics as filler ... " (High-Volume 1-2). Fly ash is also
I used in the creation of artificial reef for endangered fish and modified shingles for
roofmg.
I Concrete
The use of fly ash in concrete is relatively new, considering how long the United States
I has used traditional aggregate concrete and is a result of studies that have been conducted
by scientists, engineers, professors, and environmentalists from as early as the 1940's.
I The fly ash that is used in concrete must be converted from its original state - a solid
I 4
I
I I powder-like waste - into concrete blocks. Usually, the fly ash is mixed into the concrete
from its powder form.
I I CONCERNS ABOUT USING FLY ASH CONCRETE: THE DEBATE
I The use of fly ash for buildings and landfill is very controversial. Coal ash in its natural
pre-cleaned state was classified as a hazardous solid waste for many years. It is currently
I not considered a hazardous material by the government; it has now been classified as
merely a solid waste. Nonetheless, action must be taken to clean up the coal ash before it
I can used as a substitute for the aggregate in concrete, as well as in other coal ash projects.
I Advocates ofFly Ash Concrete
I On one side of the debate are the scientists and engineers who believe that fly ash
I concrete is safe. They argue that after mixing aggregate, lime, fly ash, and gypsum, the
concrete produced is safer than a concrete product that just uses fly ash to replace the
I aggregate. The authors of "Evaluation of the Properties ofFly Ash from Coal," presented
at the 1991 Shanghai Ash Utilization Conference, suggest that lime may increase the
I strength of fly ash concrete. "The combined lime content with fly ash is still low after 28
days and increases substantially for up to a year [because it settles].... When cement is
I replaced by fly ash, the volume ofvery fme material in the mortar and concrete is
increased" (Proceedings 12-1). What this means is that fly ash being used as a
I replacement for the aggregate in concrete should have lime mixed in with it in order for it
to withstand natural aging for more than one year.
I In 1992, a research program at the Center for By-Products Utilization at the University of
I Wisconsin - Milwaukee, sought to develop low-cost construction materials by using coal
combustion by-products like fly ash. Many different products were made such as bricks,
I blocks, and paving stones with the materials being tested. The study found that "fly ash
can be utilized as a replacement of clay in commercial manufacturing of structural
I 5
I
I I products such as bricks, blocks, paving stones, etc." (Low-Cost Ash-Derived
Construction Materials 2-1).
I The authors ofThe Supplemental Proceedings: Fourth International Conference on Fly
I Ash. Silica Fume. Slag, and Natural Pozzolans in Concrete High-Volume Fly Ash
Concrete Session agree with the Milwaukee findings. The Electric Power Research
I Institute, which funded both studies, concludes that the "[p]roper mix design can produce
high-volume fly ash (HVFA) concretes of high strength, low temperature rise, superior
I durability, and exceptional mechanical properties" (Supplemental I). This means that if
done properly, fly ash concrete may actually be superior to normal (aggregate) concrete.
I Some fly ash concrete producing companies are betting their fortunes that these findings
are true.
I ISG Resources, Incorporated use fly ash for their concrete products because they believe
I I [the] ball-bearing effect of fly ash particles creates a lubricating action when
concrete is in its plastic state. This creates benefits in Workability (concrete
I is easier to place, with less effort, responding better to vibration)....Ease of
pumping.. .Improved finishing Reduced bleeding [which] decreases
I porosity and chemical attack Reduced segregation that leads to rock
pockets and blemishes and Reduced slump loss resulting in greater working
time. (lSG 2)
I ISG Resources, Incorporated is one of the leading fly ash developers in the country, and
they currently offer FlexCrete and Dynastone products, two fly ash concrete derived
I products.
I The federal government uses fly ash concrete wherever they want. The Corps of
Engineers (COE) allows the use of fly ash as a cement replacement in concrete in all
I military construction and civil works projects. An EPRI report also mentions that the
Federal Highway Administration (FHWA), FAA, and the Environmental Protection
I Agency (EPA) will not disclose information about the safety of fly ash concrete, but they
will promote it (EPRI, Institutional 3-7).
I 6
I I Opponents ofFly Ash Concrete
I In 1995, Kurt F. Von Fay produced a report for the U. S. Department of the Interior
I entitled "Effects ofVarious Fly Ashes on Compressive Strength, Resistance to Freezing
and Thawing, Resistance to Sulfate Attack, and Adiabatic Temperature Rise of
I Concrete." In this government publication, Von Fay reported on all of the experiments
that he and his group ofscientists performed. One such experiment involved the long
I term strength of fly ash in concrete. Surprising and very scary results were discovered.
All samples ofthe concrete with fly ash in them expanded, collapsed, or otherwise failed
I (29). Sometimes, the samples failed after only 300 days ofexposure to normal natural
elements (see Appendix B). This study suggests that fly ash would not be the best
building material.
I In addition to the structural problems, there is another fuctor in using fly ash for concrete
that must be examined: the environmental aspect. According to the report Chemical
I Form and Leachability ofInorganic Trace Elements in Coal As!!, "Laboratory studies
showed that combustion conditions strongly influence the chemical form of trace
I I elements in ash produced by coal-fired power plants (i). The writers also believe that a
potential problem of fly ash is the "contamination of surfucewater and groundwater by
I trace elements as a result ofleaching ofresidues" (iii). However, trace element leachates
as well as fly ash composition are variable. Leachates are unwanted, sometimes toxic
I chemicals such as arsenic that seep out ofthe concrete and into the groundwater. Trace
elements are traces (small amounts) of the specific element such as arsenic that can leach
I into the ground. Trace elements, leachates, and fly ash
composition vary from plant to plant and are site specific due
I to the various ways the coal is burned and fly ash is collected.
"[I]fthe chemical affiliation of trace elements in ash were
I mainly dependent upon the burning conditions, it would be
possible to predict the leaching oftrace elements from knowledge of the combustion
I conditions....Coal with a lower heat content yields more leachable trace elements,
possibly because of lower combustion temperatures inside the furnace" (iii). It is easy to
I I
7
I I see, then, that the temperature at which the fly ash is originally created at can have a huge
impact on the environment.
I In 1992, the authors of the Electrical Power Research Institute's report Institutional
I Constraints to Coal Fly Ash Use in Construction ascertained that because ofcontroversy
surrounding the safety offly ash concrete, only 12 states allow fly ash to be used in
I concrete pavement. They also note that only 17 states use fly ash for structural fill, and
three states allow fly ash to be used in soil. "Many states indicated that their current rules
I and regulations do not specifically address coal fly ash utilization. Although this is the
case, some environmental agencies indicated that they do currently allow certain fly ash
I uses. In addition, the Illinois Environmental Protection Agency indicated that fly ash use
is evaluated on a case-by-case basis" (3-7). Since the report, the number of states
I allowing fly ash to be used in concrete pavement has increased to 26, although some
states still evaluate on a case-by-case basis.
I Debate Summary
I I The main problem with using fly ash concrete for buildings is the fundamental
disagreement among credible experts. One scientist or engineer believes it is safe, while
I another believes it is dangerous. Upon study of the debate, it seems that the best position
to take is that of the authors of the report Utilization ofCoal Combustion By-Products for
I Masonry Construction. "Future research is recommended in order to get better
understanding of the engineering performance, durability, and manufacturing of ash
masonry products" (iii).
I The Clean Air Act
Throughout time, changes have been made in the requirements for the collection of fly
I ash. The New Clean Air Act of 1990, signed by President Clinton, specified changes in
emissions from coal power plants. The 1970 and 1977 Clean Air Acts were the first
I I
8
I I federally regulated programs to control air pollution from emissions including fly ash.
Prior to the 1970 Act emissions were not controlled, causing pollution to the air, "fires
I caused by sparks from passing locomotives" and "claims that fluoride emissions from
aluminum smelters damage gladiolus and other crops" (Lock 3). Beyond such nuisances,
I there were serious heahh concerns. The 1990 Amendments to the Clean Air Act will,
according to the EPA, "remove 56 billion pounds per year ofair pollution, reduce by 50
I percent emissions causing acid rain, eliminate 75 percent of toxic air pollutants and
assure that all areas of the country meet national ambient air quality standards" (Lock 6).
I Thanks to the 1990 Amendments, airborne particulates (including fly ash), sulfur
dioxide, nitrogen oxides, and carbon dioxide emissions from coal are lowering.
I Environmentalists
I I
According to many environmentalists, the primary concerns about the safety of fly ash
concrete have not been addressed. They want to know: Is it safe to use coal ash, the
I residue ofburned coal, in a recycled manner, or will it cause more harm than good?
Before we can safely address the problem of hazardous coal byproducts, these questions
I must be answered. Moreover, as a nation, we need to become more informed about coal
byproducts. We need to know why and how coal byproducts are used in each ofour
regions so we can make an educated decision about whether or not we want to use
I recycled coal byproducts.
I Until the 1970's, fly ash was just another inconvenient side-effect ofburning coal that no
I one cared about. However, as the Nation started to use increasing amounts of energy, the
fly ash residue also increased. Thanks to the scientists, engineers, and environmentalists
I who pushed for reform, we have taken an unwanted residue and made it recyclable.
Now, instead of filling landfills with tons of fly ash, we can now use that same material
I to build with fly ash concrete. According to ISO, the use of fly ash instead ofcement
decreases the need for cement production, a source of "greenhouse gas" emissions. They
also state:
I I
9
I
I I For every ton ofcement manufactured, about 6.5 million BTUs ofenergy
are consumed, and one ton of carbon dioxide is released. Experts estimate
I that cement production contributes to about 7 percent of carbon dioxide
emissions from human sources. Ifall the fly ash generated each year were
I used in producing concrete, the reduction ofcarbon dioxide released from
cement production would be equivalent to eliminating 25 percent ofthe
I world's vehicles. (lSG 4 Italics mine)
I Obviously, ifwe would use the resources at our fingertips (fly ash) instead of filling up
the landfills with it, we would have a lot less pollution not only in the United States, but
I in the world.
I However, the concerns ofthe environmentalists about the safety of fly ash are not
I imaginary. According to Edgar's Coal Processing and Pollution Control. fly ash contains
arsenic, lead, chlorine, mercury, fluorine, copper, nickel, zinc, tin, chromium, sulfur,
I boron, uranium, and many other elements, although they are in trace amounts (272-273).
The buildup ofsuch elements in landfills could do a lot of damage, as could the improper
cleaning (removal) ofthe majority of these elements before the fly ash is used for
I concrete.
I I
The Marion Memorial Hospital complex has aroused the interest of some citizens. Will
the new Marion Memorial Hospital building ultimately harm as much as it heals? Given
I what we know based on the research, I do not believe so. Fly ash concrete appears to be
a safe and economical choice. More importantly, Marion Memorial Hospital, its
engineers, and the City Council should have come forward and clarified the issue with
I the public, teaching the general public about fly ash - and bottom ash, which is what they
are really using.
I I I
10
I I In The Future ofEnergy Use, Hil~ et. al., wisely note that the need for energy in our
world is expanding rapidly. With the increasing need for energy comes the increase in
I need for fuel, including coal. With an increase of coal combustion, we have an increase
ofcoal byproducts like fly ash.
I What we do with this fly ash will determine our future society.
I I I I I I I I I I I I I I
II
I
REFERENCES
I I Chemical Form and Leachability ofInorganic Trace Elements in Coal Ash. University of
Southern California Environmental Engineering Program, 1987.
I Edgar, Thomas F. Coal Processing and Pollution Control. Texas: GulfPublishing Company, 1983.
I Electric Power Research Institute. Fly Ash Structural Fill Handbook. Monroeville: GAl Consultants, Inc., 1979.
I Electric Power Research Institute. High-Volume Fly Ash Concrete Technology. Milwaukee: University of Wisconsin, 1992.
I Electric Power Research Institute. Institutional Constraints to Coal Fly Ash Use in Construction. Monroeville: GAl Consultants, Inc., 1992.
I Electric Power Research Institute. Low-Cost Ash-Derived Construction Materials. Milwaukee: University of Wisconsin, 1992.
I Electric Power Research Institute. Proceedings: Shanghai 1991 Ash Utilization Conference. Shanghai: Shanghai Research Institute ofBuilding Sciences, 1991.
I Electric Power Research Institute. Supplemental Proceedings: Fourth International
I Conference on Fly Ash. Silica Fume, Slag. and Natural Pozzolans in Concrete. Ottawa: Radian Canada Inc. and Canada Centre for Mineral and Energy Technology, 1992.
I Electric Power Research Institute. Utilization of Coal Combustion By-Products for
I Masonry Construction. Milwaukee: University of Wisconsin, 1992.
Fly Ash Resource Center, The. All Photographs ofFly Ash. 2 April 2002.
I <http://www.geocities.com/CapeCanaverallLaunchpad/ 2095/envindex.html>.
Goldstein, Richard. "New Experiment: State Grants $152,000 For Marion Hospital Project." The Southern Illinoisan. 5 July 200 I. 19 Nov. 2001. <http://www.southernillinoisan.com/rednews/2001/07/06/build/locaVLOCOO I.hlml>.
I Hill, Robert, Phil O'Keefe and Colin Snape. The Future ofEnergy Use. London: Earthscan Publications Ltd, 1995.
I I
ISG Resources Incorporated. "Workability." 2 April 2002. <http://www.flyash.com/i_workability.html>.
I Lock, Reinier, Dennis P. Harkawik LeBoeuf, Lamb, Leiby & MacRae. The New Clean
Air Act: Compliance and Opportunity. Virginia: Public Utilities Reports, Inc., 1991.
I Merritt, Roy D. Dictionary ofCoal Science and Technology. New Jersey: Noyes Publications, 1987.
I Pairsh, Rebekah. "Lake ofEgypt coal-fired power plant: cover image." Photograph. Marion, Illinois: 2002.
I Pairsh, Rebekah. "Marion Memorial Hospital's New Complex." Photograph. Marion, Illinois: 2002.
I Serati, Ray. Illinois Clean Coal Institute. "Governor Announces Grant for Coal Research and Development." 5 July 2001. State ofIllinois. 21 Aug. 2001 <http://www.icci.org/news/rnarion.html>.
I I Von Fay, Kurt F. (D. S. Department ofthe Interior). "Effucts ofVarious Fly Ashes on
Compressive Strength, Resistance to Freezing and Thawing, Resistance to Sulfate Attack, and Adiabatic Temperature Rise ofConcrete." Government Publication (Feb. 1995): 1-56.
I I I I I I I I
13
I
I I 31lODI)'!
I LOWC HIGHC CLASSY
I Figuro 12.• Expansion of fly ash mixtures with 42'" ~)of cemlntli:lllS malerials II: aboul16::) 10 1750 day. (ac:cllltatild test).
I Von Fay, Kurt F. (D. S. Department of the Interior). "Effects ofVarious Fly Ashes on Compressive Strength, Resistance to Freezing and Thawing, Resistance to Sulfate Attack, and Adiahatic Temperature Rise ofConcrete." Government Publication (Feb. 1995): 1I 56.
I I
Rebekah Pairsh
Recommended Citation
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Follow this and additional works at: http://opensiuc.lib.siu.edu/uhp_theses
This Dissertation/Thesis is brought to you for free and open access by the University Honors Program at OpenSIUC. It has been accepted for inclusion in Honors Theses by an authorized administrator of OpenSIUC. For more information, please contact [email protected].
Recommended Citation Pairsh, Rebekah, "Fly Ash Concrete: Future Foundations?" (2002). Honors Theses. Paper 141.
I I
I I I I I I I I I I Fly Ash Concrete: Future Foundations?
I by
I I
I I
I would like to thank Dr. Gerald Nelms ofthe English Department at Southern Illinois University, Carbondale for his invaluable help and advice.
I I would also like to thank Dr. John S. Mead, Director ofthe Coal Research Center at
Southern Illinois University, Carbondale, for lending much ofthe materials used in this thesis.
I I I I I I I I I
I I I I I I I I I I I I I I I I I I I
Fly Ash Concrete: Future Foundations?
Table of Contents
Advocates ofFly Ash Concrete 5
Opponents ofFly Ash Concrete 7
Debate Summary
I I PROLOGUE
It was Summer 2001. Marion Memorial Hospital ofMarion, Illinois, a small regional
I hospita~ announced its intention to build a new hospital complex that would triple its
current size. The Hospital spokesman, Tom Keirn, announced that the Hospital's
I I contractor intended to use fly ash (also known as coal ash) concrete in the buildings.
Some scientists, engineers, and environmentalists believe that fly ash material is
I environmentally safe and structurally sound. Others, however, do not. Suddenly, the
celebration ofthe new Hospital turned into controversy.
Throughout the past thirty years, many studies of the feasibility ofusing fly ash concrete
I have been conducted. Some of the scientific results were negative, including one where
the structures built collapsed 95 percent of the time. However, the majority of the
I scientific results have been positive. In one study, the strength of the concrete was found
to be better in fly ash concrete than in regular aggregate concrete. In addition to
I questions about strength, there are also questions about environmental safety. The debate
between environmentalists is one of safety for humans and the environment. Although
I fly ash is considered by most to be environmentally safe, no one can be 100 percent sure
whether daily exposure to fly ash is safe for humans to be exposed to, or if fly ash
I concrete releases dangerous chemicals into the groundwater.
I I
I I Complicating the issue even further is the lack ofcommunication that often accompanies
the use of fly ash concrete. Marion Memorial Hospital, its engineers, and the City
I Council never clarified their reasons for using fly ash concrete. As a matter of fact, fly
ash is not really being used in the Marion Memorial Hospital concrete. They are using
I bottom ash, a denser byproduct ofbuming coal that is considered safe by aU experts.
There are no buildings currently being built or that have been built with fly ash in this
I area. According to Ray Serati, reporting for The Southern Illinoisan newspaper on the
Hospital, "The project incorporates the use ofcoal bottom ash, a coal combustion by
I product, in concrete support piles for the hospital's new Medical Office Building and
Power House" (1). The project calls for the use of200 tons ofbottom ash from
I Springfield's City Water Light and Power's (CWLP) plant complex to supplant the
aggregate that is normally used in concrete.
I Still, to this date, many Marion citizens do not realize that the new complex is not being
I built with fly ash. Not only this, they also do not understand the difference between fly
ash and bottom ash. Marion Memorial Hospital and the engineers of the project do not
I seem to be concerned enough with the misconceptions of the public to come forward and
explain the issue to the community and this lack ofcommunication with the public could
I become a serious public relations problem. The lack of information given to Marion
citizens is astounding. The problem Marion citizens are faced with is that no scientist,
I engineer, public relations official, or anyone else for that matter has informed the public
about the safety ofa building composed ofbottom ash or fly ash. In doing research on
I this matter, it becomes evident that the scientific community is at a loss in how to
communicate the benefits ofusing coal ash, specifically fly ash, to the public. This
I thesis, then, will attempt to define and explain fly ash in layman's terms and hopefully,
will answer some common questions and amend some misconceptions about fly ash
I concrete.
I I FLY ASH DEFINED
I When coal is burned to create energy, specifically electric power, fine coal particles
become airborne. These airborne particles are called fly ash because they literally float
I through the air. Because of the Clean Air Act, which will be discussed in more detail
later, the fly ash particles must be collected. According to the Dictionary of Coal
I Science and Technology, these airborne particles would normally be expelled with the
gas out of the smoke stacks if it were not gathered by electrostatic precipitators (Merritt
I 149-150).
I Fly ash is collected in four different ways, but it generally uses the aid ofan electrostatic
I precipitator. The electrostatic precipitator is an apparatus that is attached to the smoke
stacks ofcoal-fired power plants. The fly ash particles have a natural static-cling, and
I this device is used "to remove the fly ash from the stack gas and to collect it" (Merritt
133), presumably with the opposite electric charge. According to Coal Processing and
Pollution Contro!, particulate (fly ash) emissions are also controlled by cyclones, wet
I scrubbers, and fabric filters - also known as a 'baghouse' (Edgar 302) - the form of
collection Southern Illinois University at Carbondale uses.
I I The Electric Power Research Institute's (EPRI's) Fly Ash Structural Fill Handbook
defines fly ash as:
a by-product of the combustion process necessary for the production of
I electrical energy at modem power stations which burn fossil fuels. It is the
very fine, light dust which is carried off in the stack gases from the boiler
I units and collected by the air pollution control equipment. Fly ash is
composed of the noncombustible mineral matter present in coal and any
I carbon which remains unburned due to incomplete combustion....
(Section 2, Page I)
I As one may discern from the definitions above, fly ash is a powder-like substance.
I However, the particles may be shaped in various sizes and compositions, depending on
I 3
I
I I the type ofcoal that is being burned. No matter what type ofcoal is being burned,
according to the federal government, fly ash only has two different classifications.
I . J'),.
.,..,-;1.0'o·V .: J'
' .. ~. -. --.....,/ I Class F Fly Ash Class C Fly Ash
I Class F fly ash is more pozzo1anic (glassy) in nature, making it ineffectual for use in
concrete. Class C fly ash, on the other hand, contains more calcium making it more
I suitable for use in concrete. Over the last three decades, many attempts have been made
to develop a useful concrete containing 15-20% fly ash. This new concrete is now being
I tested.
Miscellaneous
I I
Fly ash is utilized in many different ways. The Electric Power Research Institute's Final
Report in March 1992 noted that in addition to its use in concrete, fly ash "has been used
I in highway construction work as an embankment material, in agriculture as soil
amendments, [and] in metals and plastics as filler ... " (High-Volume 1-2). Fly ash is also
I used in the creation of artificial reef for endangered fish and modified shingles for
roofmg.
I Concrete
The use of fly ash in concrete is relatively new, considering how long the United States
I has used traditional aggregate concrete and is a result of studies that have been conducted
by scientists, engineers, professors, and environmentalists from as early as the 1940's.
I The fly ash that is used in concrete must be converted from its original state - a solid
I 4
I
I I powder-like waste - into concrete blocks. Usually, the fly ash is mixed into the concrete
from its powder form.
I I CONCERNS ABOUT USING FLY ASH CONCRETE: THE DEBATE
I The use of fly ash for buildings and landfill is very controversial. Coal ash in its natural
pre-cleaned state was classified as a hazardous solid waste for many years. It is currently
I not considered a hazardous material by the government; it has now been classified as
merely a solid waste. Nonetheless, action must be taken to clean up the coal ash before it
I can used as a substitute for the aggregate in concrete, as well as in other coal ash projects.
I Advocates ofFly Ash Concrete
I On one side of the debate are the scientists and engineers who believe that fly ash
I concrete is safe. They argue that after mixing aggregate, lime, fly ash, and gypsum, the
concrete produced is safer than a concrete product that just uses fly ash to replace the
I aggregate. The authors of "Evaluation of the Properties ofFly Ash from Coal," presented
at the 1991 Shanghai Ash Utilization Conference, suggest that lime may increase the
I strength of fly ash concrete. "The combined lime content with fly ash is still low after 28
days and increases substantially for up to a year [because it settles].... When cement is
I replaced by fly ash, the volume ofvery fme material in the mortar and concrete is
increased" (Proceedings 12-1). What this means is that fly ash being used as a
I replacement for the aggregate in concrete should have lime mixed in with it in order for it
to withstand natural aging for more than one year.
I In 1992, a research program at the Center for By-Products Utilization at the University of
I Wisconsin - Milwaukee, sought to develop low-cost construction materials by using coal
combustion by-products like fly ash. Many different products were made such as bricks,
I blocks, and paving stones with the materials being tested. The study found that "fly ash
can be utilized as a replacement of clay in commercial manufacturing of structural
I 5
I
I I products such as bricks, blocks, paving stones, etc." (Low-Cost Ash-Derived
Construction Materials 2-1).
I The authors ofThe Supplemental Proceedings: Fourth International Conference on Fly
I Ash. Silica Fume. Slag, and Natural Pozzolans in Concrete High-Volume Fly Ash
Concrete Session agree with the Milwaukee findings. The Electric Power Research
I Institute, which funded both studies, concludes that the "[p]roper mix design can produce
high-volume fly ash (HVFA) concretes of high strength, low temperature rise, superior
I durability, and exceptional mechanical properties" (Supplemental I). This means that if
done properly, fly ash concrete may actually be superior to normal (aggregate) concrete.
I Some fly ash concrete producing companies are betting their fortunes that these findings
are true.
I ISG Resources, Incorporated use fly ash for their concrete products because they believe
I I [the] ball-bearing effect of fly ash particles creates a lubricating action when
concrete is in its plastic state. This creates benefits in Workability (concrete
I is easier to place, with less effort, responding better to vibration)....Ease of
pumping.. .Improved finishing Reduced bleeding [which] decreases
I porosity and chemical attack Reduced segregation that leads to rock
pockets and blemishes and Reduced slump loss resulting in greater working
time. (lSG 2)
I ISG Resources, Incorporated is one of the leading fly ash developers in the country, and
they currently offer FlexCrete and Dynastone products, two fly ash concrete derived
I products.
I The federal government uses fly ash concrete wherever they want. The Corps of
Engineers (COE) allows the use of fly ash as a cement replacement in concrete in all
I military construction and civil works projects. An EPRI report also mentions that the
Federal Highway Administration (FHWA), FAA, and the Environmental Protection
I Agency (EPA) will not disclose information about the safety of fly ash concrete, but they
will promote it (EPRI, Institutional 3-7).
I 6
I I Opponents ofFly Ash Concrete
I In 1995, Kurt F. Von Fay produced a report for the U. S. Department of the Interior
I entitled "Effects ofVarious Fly Ashes on Compressive Strength, Resistance to Freezing
and Thawing, Resistance to Sulfate Attack, and Adiabatic Temperature Rise of
I Concrete." In this government publication, Von Fay reported on all of the experiments
that he and his group ofscientists performed. One such experiment involved the long
I term strength of fly ash in concrete. Surprising and very scary results were discovered.
All samples ofthe concrete with fly ash in them expanded, collapsed, or otherwise failed
I (29). Sometimes, the samples failed after only 300 days ofexposure to normal natural
elements (see Appendix B). This study suggests that fly ash would not be the best
building material.
I In addition to the structural problems, there is another fuctor in using fly ash for concrete
that must be examined: the environmental aspect. According to the report Chemical
I Form and Leachability ofInorganic Trace Elements in Coal As!!, "Laboratory studies
showed that combustion conditions strongly influence the chemical form of trace
I I elements in ash produced by coal-fired power plants (i). The writers also believe that a
potential problem of fly ash is the "contamination of surfucewater and groundwater by
I trace elements as a result ofleaching ofresidues" (iii). However, trace element leachates
as well as fly ash composition are variable. Leachates are unwanted, sometimes toxic
I chemicals such as arsenic that seep out ofthe concrete and into the groundwater. Trace
elements are traces (small amounts) of the specific element such as arsenic that can leach
I into the ground. Trace elements, leachates, and fly ash
composition vary from plant to plant and are site specific due
I to the various ways the coal is burned and fly ash is collected.
"[I]fthe chemical affiliation of trace elements in ash were
I mainly dependent upon the burning conditions, it would be
possible to predict the leaching oftrace elements from knowledge of the combustion
I conditions....Coal with a lower heat content yields more leachable trace elements,
possibly because of lower combustion temperatures inside the furnace" (iii). It is easy to
I I
7
I I see, then, that the temperature at which the fly ash is originally created at can have a huge
impact on the environment.
I In 1992, the authors of the Electrical Power Research Institute's report Institutional
I Constraints to Coal Fly Ash Use in Construction ascertained that because ofcontroversy
surrounding the safety offly ash concrete, only 12 states allow fly ash to be used in
I concrete pavement. They also note that only 17 states use fly ash for structural fill, and
three states allow fly ash to be used in soil. "Many states indicated that their current rules
I and regulations do not specifically address coal fly ash utilization. Although this is the
case, some environmental agencies indicated that they do currently allow certain fly ash
I uses. In addition, the Illinois Environmental Protection Agency indicated that fly ash use
is evaluated on a case-by-case basis" (3-7). Since the report, the number of states
I allowing fly ash to be used in concrete pavement has increased to 26, although some
states still evaluate on a case-by-case basis.
I Debate Summary
I I The main problem with using fly ash concrete for buildings is the fundamental
disagreement among credible experts. One scientist or engineer believes it is safe, while
I another believes it is dangerous. Upon study of the debate, it seems that the best position
to take is that of the authors of the report Utilization ofCoal Combustion By-Products for
I Masonry Construction. "Future research is recommended in order to get better
understanding of the engineering performance, durability, and manufacturing of ash
masonry products" (iii).
I The Clean Air Act
Throughout time, changes have been made in the requirements for the collection of fly
I ash. The New Clean Air Act of 1990, signed by President Clinton, specified changes in
emissions from coal power plants. The 1970 and 1977 Clean Air Acts were the first
I I
8
I I federally regulated programs to control air pollution from emissions including fly ash.
Prior to the 1970 Act emissions were not controlled, causing pollution to the air, "fires
I caused by sparks from passing locomotives" and "claims that fluoride emissions from
aluminum smelters damage gladiolus and other crops" (Lock 3). Beyond such nuisances,
I there were serious heahh concerns. The 1990 Amendments to the Clean Air Act will,
according to the EPA, "remove 56 billion pounds per year ofair pollution, reduce by 50
I percent emissions causing acid rain, eliminate 75 percent of toxic air pollutants and
assure that all areas of the country meet national ambient air quality standards" (Lock 6).
I Thanks to the 1990 Amendments, airborne particulates (including fly ash), sulfur
dioxide, nitrogen oxides, and carbon dioxide emissions from coal are lowering.
I Environmentalists
I I
According to many environmentalists, the primary concerns about the safety of fly ash
concrete have not been addressed. They want to know: Is it safe to use coal ash, the
I residue ofburned coal, in a recycled manner, or will it cause more harm than good?
Before we can safely address the problem of hazardous coal byproducts, these questions
I must be answered. Moreover, as a nation, we need to become more informed about coal
byproducts. We need to know why and how coal byproducts are used in each ofour
regions so we can make an educated decision about whether or not we want to use
I recycled coal byproducts.
I Until the 1970's, fly ash was just another inconvenient side-effect ofburning coal that no
I one cared about. However, as the Nation started to use increasing amounts of energy, the
fly ash residue also increased. Thanks to the scientists, engineers, and environmentalists
I who pushed for reform, we have taken an unwanted residue and made it recyclable.
Now, instead of filling landfills with tons of fly ash, we can now use that same material
I to build with fly ash concrete. According to ISO, the use of fly ash instead ofcement
decreases the need for cement production, a source of "greenhouse gas" emissions. They
also state:
I I
9
I
I I For every ton ofcement manufactured, about 6.5 million BTUs ofenergy
are consumed, and one ton of carbon dioxide is released. Experts estimate
I that cement production contributes to about 7 percent of carbon dioxide
emissions from human sources. Ifall the fly ash generated each year were
I used in producing concrete, the reduction ofcarbon dioxide released from
cement production would be equivalent to eliminating 25 percent ofthe
I world's vehicles. (lSG 4 Italics mine)
I Obviously, ifwe would use the resources at our fingertips (fly ash) instead of filling up
the landfills with it, we would have a lot less pollution not only in the United States, but
I in the world.
I However, the concerns ofthe environmentalists about the safety of fly ash are not
I imaginary. According to Edgar's Coal Processing and Pollution Control. fly ash contains
arsenic, lead, chlorine, mercury, fluorine, copper, nickel, zinc, tin, chromium, sulfur,
I boron, uranium, and many other elements, although they are in trace amounts (272-273).
The buildup ofsuch elements in landfills could do a lot of damage, as could the improper
cleaning (removal) ofthe majority of these elements before the fly ash is used for
I concrete.
I I
The Marion Memorial Hospital complex has aroused the interest of some citizens. Will
the new Marion Memorial Hospital building ultimately harm as much as it heals? Given
I what we know based on the research, I do not believe so. Fly ash concrete appears to be
a safe and economical choice. More importantly, Marion Memorial Hospital, its
engineers, and the City Council should have come forward and clarified the issue with
I the public, teaching the general public about fly ash - and bottom ash, which is what they
are really using.
I I I
10
I I In The Future ofEnergy Use, Hil~ et. al., wisely note that the need for energy in our
world is expanding rapidly. With the increasing need for energy comes the increase in
I need for fuel, including coal. With an increase of coal combustion, we have an increase
ofcoal byproducts like fly ash.
I What we do with this fly ash will determine our future society.
I I I I I I I I I I I I I I
II
I
REFERENCES
I I Chemical Form and Leachability ofInorganic Trace Elements in Coal Ash. University of
Southern California Environmental Engineering Program, 1987.
I Edgar, Thomas F. Coal Processing and Pollution Control. Texas: GulfPublishing Company, 1983.
I Electric Power Research Institute. Fly Ash Structural Fill Handbook. Monroeville: GAl Consultants, Inc., 1979.
I Electric Power Research Institute. High-Volume Fly Ash Concrete Technology. Milwaukee: University of Wisconsin, 1992.
I Electric Power Research Institute. Institutional Constraints to Coal Fly Ash Use in Construction. Monroeville: GAl Consultants, Inc., 1992.
I Electric Power Research Institute. Low-Cost Ash-Derived Construction Materials. Milwaukee: University of Wisconsin, 1992.
I Electric Power Research Institute. Proceedings: Shanghai 1991 Ash Utilization Conference. Shanghai: Shanghai Research Institute ofBuilding Sciences, 1991.
I Electric Power Research Institute. Supplemental Proceedings: Fourth International
I Conference on Fly Ash. Silica Fume, Slag. and Natural Pozzolans in Concrete. Ottawa: Radian Canada Inc. and Canada Centre for Mineral and Energy Technology, 1992.
I Electric Power Research Institute. Utilization of Coal Combustion By-Products for
I Masonry Construction. Milwaukee: University of Wisconsin, 1992.
Fly Ash Resource Center, The. All Photographs ofFly Ash. 2 April 2002.
I <http://www.geocities.com/CapeCanaverallLaunchpad/ 2095/envindex.html>.
Goldstein, Richard. "New Experiment: State Grants $152,000 For Marion Hospital Project." The Southern Illinoisan. 5 July 200 I. 19 Nov. 2001. <http://www.southernillinoisan.com/rednews/2001/07/06/build/locaVLOCOO I.hlml>.
I Hill, Robert, Phil O'Keefe and Colin Snape. The Future ofEnergy Use. London: Earthscan Publications Ltd, 1995.
I I
ISG Resources Incorporated. "Workability." 2 April 2002. <http://www.flyash.com/i_workability.html>.
I Lock, Reinier, Dennis P. Harkawik LeBoeuf, Lamb, Leiby & MacRae. The New Clean
Air Act: Compliance and Opportunity. Virginia: Public Utilities Reports, Inc., 1991.
I Merritt, Roy D. Dictionary ofCoal Science and Technology. New Jersey: Noyes Publications, 1987.
I Pairsh, Rebekah. "Lake ofEgypt coal-fired power plant: cover image." Photograph. Marion, Illinois: 2002.
I Pairsh, Rebekah. "Marion Memorial Hospital's New Complex." Photograph. Marion, Illinois: 2002.
I Serati, Ray. Illinois Clean Coal Institute. "Governor Announces Grant for Coal Research and Development." 5 July 2001. State ofIllinois. 21 Aug. 2001 <http://www.icci.org/news/rnarion.html>.
I I Von Fay, Kurt F. (D. S. Department ofthe Interior). "Effucts ofVarious Fly Ashes on
Compressive Strength, Resistance to Freezing and Thawing, Resistance to Sulfate Attack, and Adiabatic Temperature Rise ofConcrete." Government Publication (Feb. 1995): 1-56.
I I I I I I I I
13
I
I I 31lODI)'!
I LOWC HIGHC CLASSY
I Figuro 12.• Expansion of fly ash mixtures with 42'" ~)of cemlntli:lllS malerials II: aboul16::) 10 1750 day. (ac:cllltatild test).
I Von Fay, Kurt F. (D. S. Department of the Interior). "Effects ofVarious Fly Ashes on Compressive Strength, Resistance to Freezing and Thawing, Resistance to Sulfate Attack, and Adiahatic Temperature Rise ofConcrete." Government Publication (Feb. 1995): 1I 56.
I I
Rebekah Pairsh
Recommended Citation
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18